Water-in-oil (W/O) emulsions were investigated using light scattering and rheology to determine the effect of polyglycerol polyricinoleate (PGPR) concentration and inner aqueous phase composition on stability. Using high-pressure homogenization and 2% PGPR it was possible to obtain small and stable W/O emulsion droplets with 30% water. The emulsions were then incorporated in a water-in-oil-in-water (W/O/W) emulsion, and droplets were still present in the inner phase after one month of storage, as clearly shown by confocal microscopy. Encapsulation efficiencies were tested using a water-soluble dye, brilliant blue and a divalent cation, magnesium chloride. The encapsulation efficiency and stability of the encapsulated material depended on the nature of the material being encapsulated.

L’exploitation de pétrole s’accompagne de la modification des conditions thermodynamiques internes du puits et favorise, entre autres, la formation de dépôts minéraux pouvant obstruer les pores micrométriques de la formation rocheuse, rendant difficile l’extraction d’huile. L’efficacité du traitement anti-dépôts dépend de la concentration minimale d’inhibiteur et de la vitesse de relargage du produit. Dans ce contexte, nous avons étudié deux techniques d’encapsulation permettant d’obtenir un système préventif à libération prolongée contenant un polyélectrolyte anionique comme additif modèle. La première consiste en la formation de nanoparticules de polyélectrolytes complexés. La libération de l’actif encapsulé y a été stimulée par la modulation de la salinité du milieu. À pH basique, la libération de l’actif a lieu via le mécanisme de gonflement /dissociation des particules, à pH acide aucune libération ne parait avoir lieu car les objets précipitent. Le second système est une émulsion inverse (E/H) diluée contenant un actif modèle en phase dispersée. Ces systèmes sont stables et un faible pourcentage d’actif est libéré sous contrainte mécanique. / Many thermodynamic changes occur in reservoir rock when oil is produced. These changes enable scale formation on micrometric rock pores that can block them and impede/block oil extraction. Antiscale treatment efficiency depends on minimal inhibitor concentration and product release rate in fluids downhole. In this context, we have studied two encapsulation techniques allowing us to have a sustainable release system composed of an anionic polyelectrolyte as a model additive. The first formulation consists in formation of polyelectrolyte complexes nanoparticles. In this system, active ingredient release was stimulated through medium ionic strength modulation. Under basic conditions, release takes place in particles swelling/dissociation process; whereas, under acidic condition, particles precipitate and no release can be expected. The second system we have worked on is a diluted reverse (W/O) emulsion, in which dispersed aqueous droplets contain a model additive. These systems are stable and small additive percentage is released under mechanic strain.